ZX81 and sound

Any discussions related to the creation of new hardware or software for the ZX80 or ZX81
jp48
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Joined: Sun Nov 21, 2010 7:55 pm

ZX81 and sound

Post by jp48 »

Hi all,

I'm new here, asking some advices about generating sound by ZX81. I've heard that (1-bit) sound could be generated by cassette port and/or quickly changing FAST/SLOW states. I'm especially interested of writing some assembler code for this, if anyone could give few tips where to start. I assume I'm able to use any Z80-assembler (pasmo, tniASM, TASM etc.) or if there are some specifically ZX81 oriented cross-compiler/assembler, then using it. Z88DK at least seems to have some libraries to ZX81 too. I'm not looking for AY-chip stuff, only either of those I mentioned, also I don't have ZX81 (yet), not sure if they work with emulators at all (currently using sz81 on Linux).

All tips highly appreciated, very nice to see there's still such an amount of activity and people around this little machine !


-Jukka
sirmorris
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Joined: Thu May 08, 2008 5:45 pm

Re: ZX81 and sound

Post by sirmorris »

Hi Jukka!

Welcome aboard :)

I can't help directly as I've never tried anything like this but I'd start here:

http://www.wearmouth.demon.co.uk/zx81.htm

at the SAVE code, more specifically the PULSES label in the 'OUT-BYTE' routine.

Another great source of information is NO$'s docs here:

http://nocash.emubase.de/zxdocs.htm

Hope this helps and I'm looking forward to hearing some sounds!

PS I use the z88dk's assembler - I'll post some info about it when I get a moment.

Charlie
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kmurta
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Re: ZX81 and sound

Post by kmurta »

Hi Jukka!

Take a look at the files chariots.zip and zx81mi.zip in http://www.4shared.com/dir/n8dv5L6D/zeddy-br.html.

And, yes, it works with sz81 :)
1 x ZX81, 2 x TK85 , 1 TK82C, 1 TK95, 1 x Alphacom 32 printer, 1 x ZXpand
ZeXtender board, Joy81 - Programmable Joystick Controller, Turbo Sound 81
http://zx81.eu5.org
https://toddysoftware.itch.io/
jp48
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Joined: Sun Nov 21, 2010 7:55 pm

Re: ZX81 and sound

Post by jp48 »

Thanks sirmorris and kmurta, a lot of new stuff, the wearmouth document was probably most perfect description of 8-bit machine I've seen so far. Just downloading kmurta's archives, I'm excited especially hearing that they work in sz81 too !

Thanks very much !


-Jukka
jp48
Posts: 3
Joined: Sun Nov 21, 2010 7:55 pm

Re: ZX81 and sound

Post by jp48 »

A short question about sz81: first it is excellent emulator, I just can't find any way to take screen snapshots.
Any tips ?

Thanks !

Reading kmurta's ASM-files, excellent !


-Jukka
UKRetroGamer
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Joined: Sat Aug 28, 2010 12:42 pm

Re: ZX81 and sound

Post by UKRetroGamer »

jp48 wrote:A short question about sz81: first it is excellent emulator, I just can't find any way to take screen snapshots.
Any tips ?
If the application doesn't have a screen-dump option, you can probably do this from the Operating System.

Which OS are you using?

If you're a Windows user, Hold down the Alt key and tap the Print-Screen key while the sz81 window has focus. You can then PASTE into MSPaint and trim as appropriate.
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yerzmyey
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Re: ZX81 and sound

Post by yerzmyey »

jp48:


>Hi all,
------
Yo,

>I'm new here, asking some advices about generating sound by ZX81. I've heard that (1-bit) sound could be generated by cassette port and/or quickly changing FAST/SLOW states.
------------
Well, it can and actually it does (although 1 channel only, sadly), but amplifier on MIC port is too weak to hear it. It can be probably recorded on an old-style cassette-recorder, to hear it, I mean something like this one:
Image however I didn't try it yet.
To hear the sound normally, one would have to make probably a hardware modification (some amplifier-like electronic parts added) but I don't know if it wouldn't destroy saving. Hm.


>I'm not looking for AY-chip stuff, only either of those I mentioned, also I don't have ZX81 (yet), not sure if they work with emulators at all (currently using sz81 on Linux).
--------
I'm afraid that AY is the most resonalbe sound from ZX81 after all. The standard became a ZONX interface.
Here is an example demo for it http://sz81.svn.sourceforge.net/viewvc/ ... src.tar.gz (although it's not real music but some noises only, like I noticed) and You'd must have an EightyOne emulator with ZONX turn-ON.


>All tips highly appreciated, very nice to see there's still such an amount of activity and people around this little machine !
-----------
I You would be able to make some new 1bit engine (with 2 channels possibly?) it would be great.
IN NIHILUM REVERTERIS - a big text-adventure game for ZX81: http://tiny.pl/g2m6m
"MONOCHROME" issue 5 - (Spring 2014) free paper/PDF magazine about ZX81: http://tiny.pl/q2m44
ZX81 COMPETITIONS 2007/2009: http://zx81.republika.pl/
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kmurta
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Re: ZX81 and sound

Post by kmurta »

(although it's not real music but some noises only, like I noticed)
You are mistaken, the demo is real music, and very good by the way. See it running in my TK85:

http://www.youtube.com/watch?v=KX-HsB0Db5k

I really like to see more demos like this...
1 x ZX81, 2 x TK85 , 1 TK82C, 1 TK95, 1 x Alphacom 32 printer, 1 x ZXpand
ZeXtender board, Joy81 - Programmable Joystick Controller, Turbo Sound 81
http://zx81.eu5.org
https://toddysoftware.itch.io/
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yerzmyey
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Re: ZX81 and sound

Post by yerzmyey »

Aha. So the emulator suxx.
Even better then - that's proper sound from ZX81 with AY.

Is there any scheme of ZONX? I could ask my friend to make several such interfaces, if people from the forum are interested.
IN NIHILUM REVERTERIS - a big text-adventure game for ZX81: http://tiny.pl/g2m6m
"MONOCHROME" issue 5 - (Spring 2014) free paper/PDF magazine about ZX81: http://tiny.pl/q2m44
ZX81 COMPETITIONS 2007/2009: http://zx81.republika.pl/
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kmurta
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Re: ZX81 and sound

Post by kmurta »

Aha. So the emulator suxx.
Oh yes, the AY emulation in EO isn't perfect but it works fine in z81 and sz81.
Is there any scheme of ZONX? I could ask my friend to make several such interfaces, if people from the forum are interested.
See this: http://www.user.dccnet.com/wrigter/inde ... %20ZON.htm
1 x ZX81, 2 x TK85 , 1 TK82C, 1 TK95, 1 x Alphacom 32 printer, 1 x ZXpand
ZeXtender board, Joy81 - Programmable Joystick Controller, Turbo Sound 81
http://zx81.eu5.org
https://toddysoftware.itch.io/
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